The present invention relates to an adhesive sheet for application on skin containing an elastomer film and a process for the production thereof. More particularly, the invention relates to an adhesive sheet for application on skin which exhibits both an excellent workability during production and an excellent handleability during sticking and is so flexible so as to follow thoroughly the contour of even bent adherend after sticking and a process for the production thereof.
As the substrate (The xe2x80x9csubstratexe2x80x9d acts to support an adhesive layer) for an adhesive sheet which is applied to a movable and flexible curved surface such as skin there has heretofore been often used an elastomer film such as polyurethane having a high rubber elasticity to allow the adhesive sheet to follow the contour of the skin. Further, such an adhesive sheet is required to have a high moisture permeability and flexibility for the purpose of minimizing a feeling of physical disorder during sticking and skin irritation such as rash caused by prevention of perspiration. To this end, the substrate to be incorporated in the adhesive sheet for application on skin needs to have a low stress and an extremely low thickness. An elastomer film having a modulus of not greater than 10 N/mm2 at 50% elongation and a thickness of not greater than 70 xcexcm has been widely used.
Such an adhesive sheet containing an elastomer film has a low stress and an extremely low thickness as mentioned above and thus naturally exhibits deteriorated workability during production and deteriorated handleability in use. In order to solve this problem, an adhesive sheet having a three-layer structure containing an adhesive layer, an elastomer film and a supporting film obtained by tentatively supporting an elastomer film on a film such as synthetic resin and paper (hereinafter referred to as xe2x80x9csupporting filmxe2x80x9d) for the purpose of reinforcing the elastomer film has been proposed. The adhesive sheet is designed such that the supporting film can be peeled off and removed from the elastomer film after the sticking of the adhesive layer on the desired site during the use of the adhesive sheet.
The adhesive sheet for application on skin as mentioned above preferably has as low adhesion between the elastomer film and the supporting film as possible from the standpoint of ease of peeling of the supporting film off the elastomer film in use. However, when the adhesion between the elastomer film and the supporting film is too low, it is disadvantageous in that the elastomer film and the supporting film are peeled off each other during production. Accordingly, such an adhesive sheet is required to have an adhesion between the elastomer film and the supporting film that gives well-balanced handleability in use and workability during production. However, such an adhesion has an extremely narrow tolerance and thus can be difficultly attained invariably.
The invention has been worked out in the light of these problems. The invention is intended to provide an adhesive sheet for application on skin excellent in workability and handleability which exhibits so high an adhesivity that the elastomer film and the supporting film cannot be easily peeled off each other during production but shows a drop of adhesion between the elastomer film and the supporting film to allow the supporting film to be easily removed from the elastomer film during use and a process for the production thereof.
The inventors made extensive studies of solution to the aforementioned problems. As a result, it was found that when a component compatible with a specific adhesive and liquid or pasty at ordinary temperature is present in the supporting film after production of the adhesive sheet, there occurs a proper drop of the adhesion between the elastomer film and the supporting film that gives excellency in both producibility and handleability in use. The invention has thus been worked out.
The invention provides an adhesive sheet for application on skin which contains an adhesive layer and a laminated film containing an elastomer film having provided on one side thereof a supporting film, the adhesive layer being formed on the elastomer film side of the laminated film, wherein the adhesive layer mainly contains an acrylic polymer and both the adhesive layer and the supporting film contain a component compatible with the acrylic polymer and liquid or pasty at ordinary temperature.
The invention also provides a process for the production of an adhesive sheet for application on skin, which adhesive sheet contains an adhesive layer and a laminated film containing an elastomer film having provided on one side thereof a supporting film, the adhesive layer being formed on the elastomer film side of the laminated film, wherein the adhesive layer mainly contains an acrylic polymer and both the adhesive layer and the supporting film contain a component compatible with the acrylic polymer and liquid or pasty at ordinary temperature, which process for the production of the adhesive sheet contains applying an adhesive mainly containing the acrylic polymer containing the component compatible with the acrylic polymer and liquid or pasty at ordinary temperature to the laminated film, and then allowing a part of the liquid or pasty component contained in the adhesive to move toward the supporting film so that it is present therein.